There's been a lot going on in the world of Comet in the past couple of months. Post-JavaOne activity from the Java side has been tremendous and I was unaware of most of it until Greg Murray and Greg Wilkins mentioned the various efforts to me. <a href=http://blogs.webtide.com:80/gregw/2006/07/25/1153845234453.html">Greg's got the details of most of the Java activity, save Sun's Comet-on-Grizzly announcement. As was widely covered elsewhere, the excellent work of Juggernaut has demonstrated the Flash XMLSocket approach and integration into a widely-used, modern web framework. Of course, Nevow has been shipping some great Comet infrastructure for Twisted developers for years, but that's been a pretty small group of folks.
In other news, the Cometd project has been accepted into the Dojo Foundation. With multiple demonstrated implementations of the pre-0.1 Bayeux spec, we've got lots of momentum around solving the "last mile" problem for events to browser. Work on the spec has been bursty but I think that's contributed to keeping it simple. Right now we're tackling topic/channel globbing, event timeouts, and multiple event delivery semantics. Perhaps the most exciting thing to Bayeux to me, though, is that implementations of it lend themselves to extension and experimentation with implementing new styles of Comet transport mechanisms. The current Bayeux client in Dojo supports 4 different transport types with more on the way.
I think it's going to be interesting to see how much the ability of platforms and languages to handle Comet workloads impairs or enhances their chances. Can Ruby and PHP pull off something that'll allow them to scale? Will Twisted Python, Erlang, or full-stack Perl finally have their days in the webdev sun? Will great implementations in Java and C# hold the dynamic languages at bay?
I can't wait to find out.